What Does B1661 Mean?
This code indicates the Body Control Module (BCM) or Seat Control Module has detected a short-to-battery voltage condition in the driver's front seat upward movement circuit. This means the control circuit for raising the seat is receiving unwanted battery voltage when it should be at a lower voltage or ground, preventing normal operation. The module sets this code when it detects voltage present on the control wire when the seat up function is not commanded.
Common Causes
45%
Damaged or chafed wiring harness causing short to power wire in seat track or under seat
30%
Failed seat control switch with internal short to battery voltage
15%
Faulty seat motor or motor control relay stuck closed providing constant power
10%
Corroded or damaged connector pins at seat module or BCM causing cross-circuit short
Diagnostic Steps
1
Step 1: Perform visual inspection of all wiring under driver's seat, especially where harness contacts seat track mechanism. Look for chafed, pinched, or damaged insulation exposing copper wire that could contact power sources.
2
Step 2: Disconnect the seat control switch connector and measure voltage on the seat-up control wire at the seat motor/module side using a digital multimeter. Reading should be 0 volts with ignition on and switch disconnected; battery voltage confirms short downstream of switch.
3
Step 3: If voltage is present at motor with switch disconnected, disconnect the seat height motor connector and recheck voltage on control wire. If voltage disappears, motor or internal relay is shorted; if voltage remains, wiring harness between switch and motor has short to power.
4
Step 4: If no voltage found at motor with switch disconnected, reconnect motor and test switch operation. Use multimeter to check for proper voltage output only when up button is pressed. Constant voltage output indicates failed switch assembly.
5
Step 5: Inspect all connector terminals for corrosion, bent pins, or signs of moisture intrusion that could cause cross-circuit contamination. Pay special attention to multi-pin connectors under seat exposed to debris and liquids.
6
Step 6: After repair, clear codes, cycle seat through full range of motion multiple times, and verify code does not return. Monitor live data for proper voltage signals during seat operation.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) or Seat Control Module has detected a short-to-battery voltage condition in the driver's front seat upward movement circuit. This means the control circuit for raising the seat is receiving unwanted battery voltage when it should be at a lower voltag...
The most common cause of B1661 (Seat Driver Front Up Circuit Short To Battery) is: Damaged or chafed wiring harness causing short to power wire in seat track or under seat
Typical repair costs for B1661 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects power seat adjustment functionality. The seat position will remain fixed and cannot be adjusted upward, but does not impact vehicle operation or safety systems. Repair at convenience unless seat position prevents proper driving posture.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1661 to identify the root cause.
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Quick Info
Category
Body
System
Power Seat Control System
Difficulty
Type
Manufacturer
Recommended Tools
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